1. Field of the Invention
This invention relates to chew toys made for pets out of animal rawhide and the method of their manufacture.
2. Description of the Related Art
Rawhide pet chews are staple products sold in the consumer pet product industry. Rawhide pet chews designed particularly for dogs promote oral hygiene, provide a distraction, and reinforce the dog owner's relationship with the dog. The tough, dried rawhide of the pet chews cleans tartar and plaque off the animal's teeth when chewed. Additionally, the rawhide does not cause harm to the animal if ingested.
Unfortunately, not all animals are attracted to rawhide chews and, therefore, some pet owners cannot take advantage of this easy way to promote oral hygiene for their pets. In particular, some animals do not find the rawhide appetizing, primarily because of the lack of taste. In the typical manufacturing process of rawhide chews, the animal hides are stripped of any fat or sinew and are washed and whitened. This process inhibits spoilage and ensures a safe product for animals to ingest. However, this process also removes much of the fatty, oily taste of normal animal skin that is enticing to animals.
In order to overcome the problem of palatability of rawhide pet chews, manufacturers have attempted to add flavor to the rawhide. Methods for supplying flavor additives in the past have focused on basting or spray coating the rawhide with a gravy, marinade, or other flavor enhancement. Once coated with a gravy, the rawhide pet chew is dried so the gravy adheres to or forms a crust on the surface of the rawhide pet chew. While such surface coatings are enticing to animals, they have several drawbacks. First, once an animal starts chewing on the pet chew, the animal's saliva reconstitutes the dried gravy coating. Many times these coatings contain brightly colored dyes as well. The wet, colored, gravy coating often rubs off onto decorative surfaces on which the pet chew is laid, for example, carpeted floors and upholstered furniture, thereby soiling or staining the decorative surfaces. Additionally, once the coating is licked off by the animal, any future enticement to continue to chew the pet chew is gone and the pet chew may be ignored.
Some rawhide pet chews are manufactured from ground rawhide that is placed in a mold and either pressed together or held together with a digestible adherent. In the industry, these chews are called “munchies.” The rawhide pieces may each be coated with a flavor and/or dyed before being molded, or the finished, molded munchie may be coated and/or colored after molded. The problem with the munchie-type pet chews is that they break up of disintegrate easily when the pet begins chewing on them. Thus, not only do munchies present the same problems with the transfer of gravy or dye to carpet and furniture, the problem is spread over a wider area as bits and pieces of the munchie material break off and fall in a distributed area. These small pieces can further become hidden in deep carpet or between cushions of furniture. Additionally, because the munchies disintegrate, they do not offer ongoing or long-lasting dental benefits to the animal by allowing the animal to gnaw on a rawhide chew for an extended period of time.
U.S. Pat. No. 5,673,653 to Sherrill describes an attempt to entice animals to prolong their chewing on a pet chew by wrapping a rawhide sheet around strips of meat jerky. Because part of the jerky is wrapped inside an outer rawhide layer, the animal is enticed to continue chewing the rawhide in order to reach the jerky in the interior of the pet chew. There are, however, several drawbacks to incorporating jerky meat into a pet chew. For example, Jerky meat is a relatively expensive component to use in what should be a relatively inexpensive consumer product for pets. The raw material costs of animal meat is more expensive than low grade hides. It is also more expensive and time consuming to manufacture jerky due to the long smoking process that is necessary to prevent spoilage of the meat. Even after smoking the meat to create jerky, there is still a chance that the jerky will mold without the introduction of further preservative additives.